The aetiology of depression is not fully understood, which allows many different perspectives on aetiology to be adopted. Researchers and clinicians may be attracted to concepts of aetiology that parallel other diagnoses with which they are familiar. Such parallels may assume the role of informal models or metaphors for depressive disorders. They may even function as informal scientific theories of aetiology, energising research activities by guiding hypothesis generation and organising new knowledge. Parallels between different types of disease may ultimately prove valuable as frameworks supporting the emergence and maturation of new knowledge. However, such models may be counterproductive if their basis, which is likely to lay at least partially in analogy, is unacknowledged or overlooked. This could cause such models to appear more compelling than they really are. Listing examples of situations in which models of depression may arise from, or be strengthened by, parallels to other familiar conditions may increase the accessibility of such models either to criticism or support. However, such a list has not yet appeared in the literature. The present paper was written with the modest goal of stating several examples of models or metaphors for depression.

This paper adopted narrative review methods. The intention was not to produce a comprehensive list of such ideas, but rather to identify prominent examples of ways of thinking about depression that may have been invigorated as a result parallels with other types of disease.

Eight possible models are identified: depressive disorders as chemical imbalances (e.g., a presumed or theoretical imbalance of normally balanced neurotransmission in the brain), degenerative conditions (e.g., a brain disease characterised by atrophy of specified brain structures), toxicological syndromes (a result of exposure to a noxious psychological environment), injuries (e.g., externally induced brain damage related to stress), deficiency states (e.g., a serotonin deficiency), an obsolete category (e.g., similar to obsolete terms such as ‘consumption’ or ‘dropsy’), medical mysteries (e.g., a condition poised for a paradigm-shifting breakthrough) or evolutionary vestiges (residual components of once adaptive mechanisms have become maladaptive in modern environments).

Conceptualisation of depressive disorders may be partially shaped by familiar disease concepts. Analogies of this sort may ultimately be productive (e.g., through generating hypotheses by analogy) or destructive (e.g., by structuring knowledge in incorrect, but intellectually seductive, ways).

Seasonal as well as weekly cycles in suicide have been described, replicated and poorly understood for a long time. In Western countries, suicides are typically least frequent on weekends and most frequent on Mondays and Tuesdays. To improve understanding of this phenomenon a strategy is required which focuses on anomalous findings beyond the regular patterns. Here, we focused on instances where the weekly suicide patterns disappear or are interrupted.

We used data from Swiss and Austrian mortality statistics for the periods 1969–2010 and 1970–2010, respectively. First, the data were cross-tabulated by days of the week and the available socio-demographic information (sex, age, religious affiliation and region). Second, time series of cumulated daily frequencies of suicide were analysed by seasonal Autoregressive Integrated Moving Average (ARIMA) models which included intervention effects accounting for Easter and Pentecost (Whit) holidays.

First, the cross tabulations showed that weekly cycles may be smoothed above all in young persons and smoothed in drowning, jumping and car gas exhaustion suicides. Second, the ARIMA analyses displayed occasional preventive effects for holidays Saturdays and Sundays, and more systematic effects for holiday Mondays. There were no after effects on Tuesdays following holiday Mondays.

In general, the weekend dip and the Monday backlog effect in suicide show striking similarities to the Advent season effect and are interpretable within the same template. The turning points between low and high frequencies possibly provide promising frames for the timing of prevention activities.

This study evaluated the measurement invariance of the strengths and difficulties questionnaire (SDQ) self-report among adolescents from seven different nations.

Data for 2367 adolescents, aged 13–18 years, from India, Indonesia, Nigeria, Serbia, Turkey, Bulgaria and Croatia were available for a series of factor analyses.

The five-factor model including original SDQ scales emotional symptoms, conduct problems, hyperactivity–inattention problems, peer problems and prosocial behaviour generated inadequate fit degree in all countries. A bifactor model with three factors (i.e., externalising, internalising and prosocial) and one general problem factor yielded adequate degree of fit in India, Nigeria, Turkey and Croatia. The prosocial behaviour, emotional symptoms and conduct problems factor were found to be common for all nations. However, originally proposed items loaded saliently on other factors besides the proposed ones or only some of them corresponded to proposed factors in all seven countries.

Due to the lack of a common acceptable model across all countries, namely the same numbers of factors (i.e., dimensional invariance), it was not possible to perform the metric and scalar invariance test, what indicates that the SDQ self-report models tested lack appropriate measurement invariance across adolescents from these seven nations and it needs to be revised for cross-country comparisons.

Previous population-based studies did not support the view that biological and genetic causal models help increase social acceptance of people with mental illness. However, practically all these studies used un-labelled vignettes depicting symptoms of the disorders of interest. Thus, in these studies the public's reactions to pathological behaviour had been assessed rather than reactions to psychiatric disorders that had explicitly been labelled as such. The question arises as to whether results would have been similar if respondents had been confronted with vignettes with explicit mention of the respective diagnosis.

Analyses are based on data of a telephone survey in two German metropolises conducted in 2011. Case-vignettes with typical symptoms suggestive of depression or schizophrenia were presented to the respondents. After presentation of the vignette respondents were informed about the diagnosis.

We found a statistically significant association of the endorsement of brain disease as a cause with greater desire for social distance from persons with schizophrenia. In major depression, this relation was absent. With both disorders, there was no statistically significant association between the endorsement of hereditary factors as a cause and social distance.

Irrespective of whether unlabelled or labelled vignettes are employed, the ascription to biological or genetic causes seems not to be associated with a reduction of the public's desire for social distance from people with schizophrenia or depression. Our results corroborate the notion that promulgating biological and genetic causal models may not help decrease the stigma surrounding these illnesses.

To determine whether disparities exist in mental health care provision to immigrants and Italian citizens with severe mental illness in Bologna, Italy.

Records of prevalent cases on 31/12/2010 with severe mental illness and ≥1 contact with Community Mental Health Centers in 2011 were extracted from the mental health information system. Logistic and Poisson regressions were carried out to estimate the probability of receiving rehabilitation, residential or inpatient care, the intensity of outpatient treatments and the duration of hospitalisations and residential care for immigrant patients compared to Italians, adjusting for demographic and clinical covariates.

The study population included 8602 Italian and 388 immigrant patients. Immigrants were significantly younger, more likely to be married and living with people other than their original family and had a shorter duration of contact with mental health services. The percentages of patients receiving psychosocial rehabilitation, admitted to hospital wards or to residential facilities were similar between Italians and immigrants. The number of interventions was higher for Italians. Admissions to acute wards or residential facilities were significantly longer for Italians. Moreover, immigrants received significantly more group rehabilitation interventions, while more social support individual interventions were provided to Italians.

The probability of receiving any mental health intervention is similar between immigrants and Italians, but the number of interventions and the duration of admissions are lower for immigrants. Data from mental health information system should be integrated with qualitative data on unmet needs from the immigrants' perspective to inform mental health care programmes and policies.

Despite the advances in child maltreatment research, there is still the need for comprehensive information about how abuse affects a broad range of categories of young adult functioning, and the extent to which these vary by sex. We examined the associations between child physical abuse (PA) and sexual abuse (SA) and six areas of functioning (mental health, physical health, life satisfaction, illegal substance use, alcohol problems and daily smoking).

Data were obtained from the 1983 Ontario Child Health Study and follow-up in 2000/2001 (n = 1893). Multilevel regression estimated the adjusted associations for PA (with severity) and SA with each of the outcomes. Estimates with an entire sample were presented with sex-by-abuse interactions to examine sex differences and then presented separately by sex.

In the adjusted model, severe PA and SA were associated with impairment in mental health, and both forms of PA (severe and non-severe) and SA were associated with low life satisfaction. In addition, severe PA was associated with illegal substance use. Child abuse variables were not associated with poor physical health, alcohol problems or smoking. Although sex-stratified analyses revealed different patterns, there was no significant sex difference in the integrated sample.

This is among the first community-based studies to show a strong association between child PA and SA and low life satisfaction in young adults. The abuse effects were similar for both sexes.